1. Field of the Invention
The present invention relates to a beamformed wireless communication system. More particularly, the present invention relates to an apparatus and a method for uplink beam alignment for initial access of a mobile station in a beamformed wireless communication system.
2. Description of the Related Art
To meet wireless data traffic demand continuously increasing, wireless communication systems are advancing for supporting a high data rate. For example, to increase the data rate, the wireless communication system is under development to enhance spectral efficiency based on communication techniques such as Orthogonal Frequency Division Multiple Access (OFDMA) and Multiple Input Multiple Output (MIMO).
However, as the demand for smart phones and tablet Personal Computers (PCs) increases and accordingly high traffic applications increase, the demand for data traffic correspondingly increases and thus it is hard to satisfy the increased wireless data traffic demand merely with related-art technologies such as spectral efficiency enhancement.
To address this shortcoming, a wireless communication system using an Ultra-High Frequency (UHF) band is attracting much attention.
When supporting the wireless communication over the UHF band, the wireless communication system is subject to increasing propagation losses such as path loss or return loss, due to frequency properties of the frequency band. As a result, the propagation distance is shortened because of the propagation loss and the service coverage area of the wireless communication system using the ultra-high frequency band is reduced.
The wireless communication system using the UHF band can expand its service coverage area by alleviating the path loss of the propagation using a beamforming technique and lengthening the propagation distance.
By use of the beamforming technique, a transmitting stage can make a plurality of transmit beam patterns of different directions. A receiving stage may receive a plurality of receive beam patterns of different directions.
As such, when using the beamforming technique, the transmitting stage and the receiving stage of the wireless communication system require a technique for selecting the transmit beam pattern and the receive beam pattern so as to achieve optimal transmission efficiency.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.